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Bordoni P.,Italian National Institute of Geophysics and Volcanology | Del Monaco F.,University of LAquila | Milana G.,Italian National Institute of Geophysics and Volcanology | Tallini M.,University of LAquila | Haines J.,Institute of Geological and Nuclear science Ltd
Bulletin of the Seismological Society of America | Year: 2014

The city of L'Aquila is built on a deep intramontane basin filled by silty clay of lacustrine origin with average S-wave velocity of about 725 m/s, topped by a calcareous breccias unit with a higher speed of about 900 m/s. New geologic and geophysical investigations following the 6 April 2009 Mw 6.3 L'Aquila, Italy, earthquake have allowed us to develop a new velocity model for the basin deposits that, coupled with the inversion of velocity, includes lateral velocity variations in the top breccia layer and a newly found red silts unit, the Limi Rossi del Colle dell'Aquila (LRCA). The city area where the LRCA unit outcrops is correlated with clusters of reinforced concrete buildings that collapsed in the normal faulting earthquake. We simulate the 2D seismic response of this new velocity model along two orthogonal cross sections and compare the synthetic spectral ratios to the experimental ones evaluated using aftershock recordings. As a result, taking into account the full scatter about the mean of the observed spectral ratios, we are able to predict not only the main features of the primary observed low-frequency resonance peak, but also the level of amplification at high frequency at most of the sites investigated. Source


Waheed S.,Pakistan Institute of Nuclear Science and Technology | Jaafar M.Z.,University of Bristol | Siddique N.,Pakistan Institute of Nuclear Science and Technology | Markwitz A.,Institute of Geological and Nuclear science Ltd | Brereton R.G.,University of Bristol
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2012

A Gent sampler was used to collect 379 pairs of filters from Nilore, a suburban area of Islamabad city. The study was designed to assess the concentration variations of trace elements in fine and coarse particulate matter due to anthropogenic activities and naturally occurring events. Source identification was performed by applying MATLAB software for principal component analysis (PCA), and cluster analysis (CA). The average fine and coarse particulate masses during the study period were 15.1 ± 11.9 and 37.3 ± 28.0 μg/m 3 respectively which complies with the 24-h air quality limits set by the government of Pakistan. The application of PCA to PM2.5 data suggests the PM contribution from sources such as soil, automobile exhaust and coal combustion, road dust and wearing of tyres, wood combustion, biomass burning and fertilizers and fungicides whereas for the PM2.5-10 data shows signatures of suspended soil, automobile exhaust, road dust and wearing of tyres, wood and biomass burning, refuse incineration, Ni smelter, fertilizers and fungicides are obtained. Cluster analysis of PM2.5 and PM2.5-10 datasets reveals that there are mainly three contributory pollution sources and these are suspended soil particles, automobile related sources and wood and coal combustion. © 2012 Copyright Taylor and Francis Group, LLC. Source


Begum B.A.,Atomic Energy Center | Hossain A.,Jahangirnagar University | Nahar N.,Jahangirnagar University | Markwitz A.,Institute of Geological and Nuclear science Ltd | Hopke P.K.,Clarkson University
Aerosol and Air Quality Research | Year: 2012

The results from 1-year of measurements of PM2.5, organic carbon (OC) and black carbon (BC) concentrations are presented for an urban traffic-influenced site, the Farm Gate in Dhaka, Bangladesh. The measurements were based on sampling using two Air Metrics simultaneously operating samplers. The concentrations of OC and BC concentrations in PM2.5 varied from 5-96 μg/m3 and 4-48 μg/m3, respectively. The concentrations of PM2.5 varied from 11-328 μg/m3. The annual particulate organic matter (POM) accounted for 46 ± 11% in PM2.5whereas BC stayed at 33 ± 12%. The effects of meteorological conditions on the variability of OC and BC concentration were examined and the contribution of secondary organic aerosol to the total OC was calculated. The concentrations of OC and BC relative to the total PM2.5are high and have good correlation with wind speed and temperature. The OC/BC ratio correlated with wind speed, temperature and sulfur concentration. Based on these relationships, it can be concluded that both local and regional sources of OC and BC are important. The local sources are traffic, coal and biomass burning. Distant sources include areas where there is extensive agricultural burning. © Taiwan Association for Aerosol Research. Source


Khan A.H.,Post Box No. 1214 | Adnan S.,Post Box No. 1214 | Markwitz A.,Institute of Geological and Nuclear science Ltd | Siddique N.,Pakistan Institute of Nuclear Science and Technology | Waheed S.,Pakistan Institute of Nuclear Science and Technology
Chemometrics and Intelligent Laboratory Systems | Year: 2011

This paper reports the analysis of a multiblock environmental dataset consisting of 176 samples collected in Islamabad Pakistan between February 2006 and August 2007. The concentrations of 32 elements in each sample were measured using Proton Induced X-ray Emission plus black carbon for both coarse and fine particulate matter. Six meteorological parameters were also recorded, namely maximum and minimum daily temperatures, humidity, rainfall, windspeed and pressure. The data were explored using Principal Components Analysis (PCA), Partial Least Squares (PLS), Consensus PCA, Multiblock PLS, Mantel test, Procrustes analysis and the RV coefficient. Seasonal trends can be identified and interpreted. Using the elemental composition of the particulates it is possible to predict meteorological parameters. Based on the models from PLS, it is possible to use elemental composition in the airborne particulates matter (APM) to predict meteorological parameters. The results from block similarity measures show that fine APM resembles meteorological parameters better than coarse APM. Multiblock PLS models however are not better than classical PLSR. This paper also demonstrates the potential of multiblock approach in environmental monitoring. © 2011 Elsevier B.V. Source


Siddique N.,Pakistan Institute of Nuclear Science and Technology | Waheed S.,Pakistan Institute of Nuclear Science and Technology | Daud M.,Pakistan Institute of Nuclear Science and Technology | Markwitz A.,Institute of Geological and Nuclear science Ltd | Hopke P.K.,Clarkson University
Journal of Radioanalytical and Nuclear Chemistry | Year: 2012

Over a 1,000 pairs of coarse and fine filters were collected using Gent samplers and polycarbonate filters from three sites in Islamabad from the period 1998 to 2010. The black carbon in these samples was determined by reflectance measurement while their elemental composition were determined using the techniques of instrumental neutron activation analysis, ion beam analysis and X-ray fluorescence spectrometry. Islamabad is a well planned and relatively small city as compared to Lahore or Karachi therefore its air quality is better than the air quality of other major Pakistani cities. It was found that the new air quality standards being implemented by the Pakistani government on the 1st of January 2012 may not be attained even in Islamabad without the implementation of control and remedial measures. An overview of the elemental data obtained and calculation of enrichment factors shows that the particles in Islamabad originate from re-suspended soil, vehicular emissions and coal combustion. However further work is required for identification of pollution sources and their origin. © 2012 Akadémiai Kiadó. Source

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